<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>generator function</title>
  <script>
    function * show () {
      console.log('a')
      yield
      coonsole.log('b')
    }
    
    const obj = show()
    obj.next()
    obj.next()
  </script>
</head>
<body>
  
</body>
</html>